Metal Hydride Wire

Abstract

A wire 2 formed from a metal hydride containing deuterium and / or tritium is disclosed. For example, the wire may be formed from aluminium deuteride. A pulsed power source 4 connected to one or more of

Description

This invention relates to a wire for receiving and concentrating a pulse of power, in particular a wire in a Z-pinch orX-pinch configuration for receiving and concentrating a pulse of power. In order to generate a large concentration of energy, e.g. for application to fusion power or a neutron source, a large pulse of power may be applied to a deuterated plastic fibre. The deuterated plastic fibre may be arranged in a Z-pinch or X-pinch configuration such that when a pulse of power is applied (e.g. by a pulsed power source), a large concentration of energy is generated in the fibre. Owing to the deuterium in the deuterated plastic fibre, this provides the necessary fuel for application to fusion power or a neutron source. However, deuterated plastic fibres have a relatively large diameter and a relatively low conductivity. This makes it difficult to concentrate the energy from the pulsed power source into the fibre to generate high enough energy densities for application to fusion power or a neutron source. The aim of the present invention is to provide an improved device for neutron generation. When viewed from a first aspect the invention provides a wire for receiving and concentrating a pulse of power, wherein the wire comprises a metal hydride comprising deuterium and / or tritium. The present invention also extends to a system for producing a localised concentration of energy, wherein the system comprises a pulsed power source and a metal hydride wire comprising deuterium and / or tritium for receiving and concentrating a pulse of power, wherein the pulsed power source is connected to the metal hydride wire and the pulsed power source is arranged to generate a pulse of power and deliver the pulse of power into the metal hydride wire, wherein the metal hydride wire is arranged to concentrate the pulse of power at a location in the metal hydride wire. The present invention relates to a wire for receiving and concentrating a pulse of power. The wire comprises (e.g. is made from) a metal hydride, with the metal hydride comprising deuterium (i.e. metal deuteride) and / or tritium (i.e. metal tritide) as the hydride. It will be appreciated that by providing a metal hydride wire (containing deuterium and / or tritium as the hydride) for applying a pulse of power to, an improved device for concentrating the pulse of power may be obtained, e.g. compared to a deuterated plastic fibre. This is because a metal hydride wire will generally have a (e.g. significantly) higher conductivity than a fibre made from deuterated plastic and may be able to be made with (e.g. drawn out into) a smaller diameter, owing to its greater ductility. The greater conductivity of the metal hydride wire means that it is easier to apply the pulse of power into the wire and the smaller diameter helps to increase the concentration of the pulse of power applied to the wire. The Applicant has appreciated that metal wires (e.g. in a Z-pinch orX-pinch configuration) are used in the generation of x-rays, where the energy concentration in the hot spot at the pinch, which produces hard x-rays at sub-micron wavelength, may contain high enough energy densities for application to fusion power or a neutron source. Therefore, by providing a metal wire that contains deuterium and / or tritium in the hydride, the necessary fuel is provided in the wire itself where the energy is being concentrated when a pulse of power is applied to the wire, such that the metal hydride wire of the present invention may be able to be used for application to fusion power or a neutron source Furthermore, compared to arrangements for application to fusion power or a neutron source that use deuterium-tritium (DT) ice, it will be appreciated that the metal hydride wire of the present invention does not require any cryogenics for operation and may be able to provide a higher density of deuterium and / or tritium. In addition, the metal hydride wires of the present invention may be relatively inexpensive to produce. The metal hydride of the wire may comprise any suitable and desired metal hydride that comprises deuterium and / or tritium. In a preferred embodiment the wire comprises a conductive metal hydride (that comprises deuterium and / or tritium). In a preferred embodiment the wire comprises aluminium hydride (that comprises deuterium and / or tritium). Preferably the metal hydride (that comprises deuterium and / or tritium) is metastable (e.g. at standard temperature and pressure), e.g. stable for at least ten minutes, e.g. at least twenty minutes. Preferably the relative concentration of deuterium and / or tritium in the metal hydride (to the metal) is greater than 1%, e.g. greater than 5%, e.g. greater than 10%, e.g. greater than 20%, e.g. greater than 50% by number density. Thus the concentration by number density (of the deuterium atoms and / or tritium atoms to the metal atoms) may, in some embodiments, even be as high as up to 300%, i.e. when the metal hydride is fully saturated by deuterium or tritium. The metal hydride wire may be manufactured in any suitable and desired way. In a preferred embodiment the metal hydride wire is manufactured using ion bombardment or pressurisation (e.g. using deuterium and / or tritium as appropriate), i.e. to convert a metal into a metal hydride. Preferably the metal hydride wire is manufactured by subjecting a metal wire to ion bombardment or pressurisation (e.g. using deuterium and / or tritium as appropriate). In this way, a large quantity of deuterium and / or tritium may be able to be loaded into the metal. The metal hydride wire may have any suitable and desired dimensions. In a preferred embodiment the metal hydride wire has a diameter that is less than 1 mm, e.g. less than 100 microns, e.g. less than 50 microns, e.g. less than 20 microns. Providing a metal hydride wire having a small diameter helps to increase the concentration of the energy from the pulsed power source that is dissipated in the wire. The system of the present invention, which comprises a pulsed power source (e.g. a pulsed power generator) arranged to generate and deliver a pulse of power into the metal hydride wire, means that the metal hydride wire is preferably subject to very fast increasing current. Thus preferably the pulsed power source is arranged to generate (and deliver into the metal hydride wire) a large, quickly rising current, e.g. over a very short period of time. Preferably the pulsed power source is arranged to generate and deliver a current pulse that increases at a rate of greater than 0.5 kA / ns, e.g. greater than 1 kA / ns. Preferably the metal hydride wire is arranged to dissipate the pulse of power into the metal hydride wire over a very short space of time, such that a large, localised concentration of energy may be produced. The metal hydride wire may be provided in any suitable and desired configuration, e.g. in the system of the present invention. In a preferred embodiment the system comprises an array of metal hydride wires, each connected to the pulsed power source, wherein the pulsed power source is arranged to deliver the pulse of power into each of the metal hydride wires, and wherein the array of metal hydride wires is arranged to concentrate the pulse of power at a location in the array of metal hydride wires. The array may comprise any suitable and desired number of metal hydride wires. The metal hydride wire or array of metal hydride wires may be arranged in any suitable and desired configuration, e.g. to concentrate the pulse of power at a location in the array of metal hydride wires. In a preferred embodiment (e.g. each of) the metal hydride wire(s) (e.g. in the array) comprises a Z-pinch (a single length of wire) or X-pinch (two or more wires connected (e.g. twisted) at a crossing point). Arranging the (e.g. array of) wire(s) in this configuration helps to creates a hot spot (i.e. a localised concentration of energy) in the (e.g. array of) metal hydride wire(s) (e.g. at the crossing point of an X-pinch) when the pulse of power is applied to the metal hydride wire(s). Preferably, e.g. when the metal hydride wire comprises a Z-pinch, one or more perturbations may be formed in the metal hydride wire, to create a point at which the pulse of power may be concentrated when it is applied to the metal hydride wire. However natural perturbations may be relied upon to provide this as they may be sufficient to create a point at which the pulse of power may be concentrated. Thus preferably the metal hydride wire is arranged to concentrate a pulse of power at a (e.g. natural) perturbation in the wire. The (e.g. array of) metal hydride wire(s) are preferably connected between two electrodes, wherein the electrodes are connected to the pulsed power source (to provide the connection between the pulsed power source and the metal hydride wire(s)). The electrodes may comprise any suitable and desired type of electrodes. In a preferred embodiment the electrodes comprise (e.g. sintered) tungsten carbide or tungsten copper composite. In a preferred embodiment the electrodes are cone-shaped (e.g. with the narrow end of the cone being connected to the metal hydride wire(s)). When the system comprises an array of metal hydride wires, the array of metal hydride wires may be arranged in an axial or a radial configuration, e.g. connected between the (electrodes of the) pulsed power source. Thus, for example, the wires in the array of metal hydride wires may be parallel to each other or radiating out from each other (e.g. when (e.g. each of) the metal hydride wires comprise Z-pinch wires). In such an array, preferably the array is arranged to concentrate the pulse of power at a central axis of the array of metal hydride wires (e.g. the central axis parallel to the metal hydride wires (when the metal hydride wires are arranged in an axial configuration) or the central axis from which the metal hydride wires radiate (when the metal hydride wires are arranged in a radial configuration). For example, the pulse of power may induce ablation and radial implosion of the metal hydride wires towards the central axis of the array. The electrodes may be configured in any suitable and desired way, e.g. to suit the configuration of the array of wires. Thus, for example, the electrodes may be extended longitudinally, may comprise a disc, an annulus, etc.. When the array metal hydride wires comprise an X-pinch, any suitable and desired number of wires may be arranged to cross at a point, e.g. 2, 3, 4 or more. The localised concentration of energy that is produced in the (e.g. array of) metal hydride wire(s) may be used for any suitable and desired application. In a preferred embodiment the localised concentration of energy is used for application to fusion power or to a (e.g. compact, intense) neutron source. Thus the invention extends to use of the wire or system of the present invention for application to fusion power or to a (e.g. compact, intense) neutron source. A number of preferred embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 shows schematically a system including a Z-pinch wire in accordance with an embodiment of the present invention; Figures 2, 3 and 4 each show schematically an array of Z-pinch wires in accordance with embodiments of the present invention; and Figure 5 shows schematically an X-pinch configuration in accordance with an embodiment of the present invention. Z-pinch and X-pinch configurations of wires are used for receiving and concentrating a pulse of power, e.g. for application to fusion power or to a neutron source. Figure 1 shows schematically a system 1 including a Z-pinch wire 2 in accordance with an embodiment of the present invention. The system 1 includes a Z-pinch wire 2 that is connected to a pulsed power source 4 via two cone-shaped electrodes 6. The Z-pinch wire 2 is made from aluminium deuteride. The aluminium deuteride wire 2, which has a diameter of approximately 40 microns is manufactured by exposing an aluminium wire to ion bombardment by deuterium ions. In operation, the pulsed power source 4 generates and delivers a current pulse to the Z-pinch aluminium deuteride wire 2. The current pulse is a pulse of large, quickly rising current (having a gradient of greater than 1 kA / ns) that is generated and dissipated into the aluminium deuteride wire 2 in a short period of time. A natural perturbation in the aluminium deuteride wire 2 causes the energy of the current pulse to be concentrated at this point, thus creating a hot spot of a very intense concentration of energy. This localised concentration of the energy from the current pulse may generate high enough energy densities for application to fusion power or a neutron source. The deuterium in the aluminium deuteride wire 2. Any suitable and desired number and configuration of X-pinch and / or Z-pinch wires may be provided between the electrodes 6 in the system 1 shown in Figure 1. A (non-exhaustive) number of examples will now be described with reference to Figures 2 to 5. Figure 2 shows schematically an array of Z-pinch wires in accordance with an embodiment of the present invention. The array 11 includes multiple aluminium deuteride wires 12 that are connected axially in parallel between two axially spaced circular disc electrodes 16 (such electrodes and wires may therefore be provided instead of the electrodes and wire in the system shown in Figure 1). Figure 3 shows an array of Z-pinch wires in accordance with another embodiment of the present invention. The array 21 includes a first set of multiple aluminium deuteride wires 22 that are connected axially in parallel between two axially spaced circular ring electrodes 26 and a second set of multiple aluminium deuteride wires 23 that are connected in parallel between a further two axially spaced circular ring electrodes 27, concentrically within the other electrodes 26 and wires 22. (Again, the configuration of the electrodes and wires may be provided instead of the electrodes and wire in the system shown in Figure 1.) Figure 4 shows an array of Z-pinch wires in accordance with another embodiment of the present invention. The array 31 includes multiple aluminium deuteride wires 32 that are connected radially between two concentric circular ring electrodes 36 (again, such electrodes and wires may be provided instead of the electrodes and wire in the system shown in Figure 1). Figure 5 shows two aluminium deuteride wires 42 in an X-pinch configuration 41 in accordance with another embodiment of the present invention. The two (or more) aluminium deuteride wires 42 are connected in parallel between two electrodes 46 and are connected to each other (e.g. by twisting the wires 42 together) at a crossing point 45. (Again, such electrodes and wires may be provided instead of the electrodes and wire in the system shown in Figure 1.) Operation of the Z-pinch and X-pinch wire configurations shown in Figures 2 to 5 operate, when used in a system such as that shown in Figure 1, in a similar manner to the single Z-pinch wire in Figure 1, except that the current pulse applied to the electrodes by the pulsed power source will induce ablation and radial implosion, e.g. of the cylindrical wire array shown in Figure 2, towards the central axis of the array. For the X-pinch configuration 41 shown in Figure 5, the localised concentration of energy will generally be at the crossing point 45 of the two wires 42. It will be seen from the embodiments outlined above that the present invention provides a metal hydride wire (containing deuterium and / or tritium) for receiving and concentrating a pulse of power. It will be appreciated that by providing a metal hydride wire (containing deuterium and / or tritium as the hydride) for applying a pulse of power to, an improved device for concentrating the pulse of power may be obtained, e.g. compared to a deuterated plastic fibre. This is owing, in at least some embodiments, to the high conductivity of the metal hydride wire (e.g. compared to a fibre made from deuterated plastic) and the ability to be able to form a wire having a relatively small diameter (again, for example, compared to a fibre made from deuterated plastic). This helps to be able to apply a pulse of power effectively into the wire and to generate a localised concentrate of the energy from the pulse of power in the wire. It will be appreciated that a number of variations to the embodiments of the invention shown with reference to the drawings may also be provided. For example, the wires may be formed from any suitable and desired metal hydride (containing deuterium and / or tritium), such as aluminium tritide, or a different metal deuteride or tritide. Also, for example, in the Z-pinch and X-pinch configurations, any suitable and desired number of wires may be connected between the electrodes, in any suitable and desired configuration. For example, in the X-pinch configuration, any suitable and desired number of wires may be arranged to be connected to each other at the crossing point. 05 24

Claims

1. A wire for receiving and concentrating a pulse of power, wherein the wire comprises a metal hydride comprising deuterium and / or tritium;5 wherein the wire comprises aluminium hydride comprising deuterium and / ortritium.

2. A wire as claimed in claim 1, wherein the wire comprises a conductive metal hydride comprising deuterium and / or tritium.

103. A wire as claimed in claim 1 or 2, wherein the metal hydride comprising deuterium and / or tritium is metastable.

4. A wire as claimed in any one of the preceding claims, wherein the relative 15 concentration of deuterium and / or tritium in the metal hydride to the metal is greater than 1%, e.g. greater than 5%, e.g. greater than 10%, e.g. greater than 20%, e.g. greater than 50%, e.g. greater than 100%, by number density.

5. A wire as claimed in any one of the preceding claims, wherein the metal 20 hydride wire has a diameter that is less than 1 mm, e.g. less than 100 microns, e.g.less than 50 microns, e.g. less than 20 microns.

6. A wire as claimed in any one of the preceding claims, wherein the metal hydride wire is arranged to concentrate a pulse of power at a perturbation in the 25 wire.

7. A system for producing a localised concentration of energy, wherein thesystem comprises a pulsed power source and a metal hydride wire comprising deuterium and / or tritium for receiving and concentrating a pulse of power, wherein 30 the wire comprises aluminium hydride comprising deuterium and / or tritium; and wherein the pulsed power source is connected to the metal hydride wire and the pulsed power source is arranged to generate a pulse of power and deliver the pulse of power into the metal hydride wire, wherein the metal hydride wire is arranged to concentrate the pulse of power at a location in the metal hydride wire.05 248. A system as claimed in claim 7, wherein the system comprises an array of metal hydride wires, each connected to the pulsed power source; wherein the pulsed power source is arranged to deliver the pulse of power into each of the metal hydride wires; and wherein the array of metal hydride wires is arranged to 5 concentrate the pulse of power at a location in the array of metal hydride wires.

9. A system as claimed in claim 8, wherein the array of metal hydride wires is arranged to concentrate the pulse of power at a central axis of the array of metal hydride wires.1010. A system as claimed in claim 7, 8 or 9, wherein the metal hydride wire or wires are arranged in a Z-pinch or X-pinch configuration.

11. A system as claimed in any one of claims 7 to 10, wherein the metal hydride 15 wire or wires are connected between two electrodes, wherein the electrodes are connected to the pulsed power source.

12. Use of the metal hydride wire as claimed in any one of claims 1 to 6 or the system as claimed in any of claims 7 to 11 for application to fusion power or for 20 application to a neutron source.

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